Brake question

Lesson #1: NEVER let anyone else drive your car. Even if you're in the car. There have been WAY too many Mustangs lost because they let a friend drive their car. While this was a minor bit of damage (compared to totaling the car), it could have been worse.

You could have a bent axle. I had that happen on the donor car for my current Cobra conversion. The wheel didn't look bent, but it would hang up every time the wheel rotated around. I took off the wheel and the caliper & rotor, put the car in neutral and had a friend slowly rotate the other wheel. I could then see the axle wobbling slightly - it was definitely bent. I suggest you give that a try and see if the axle is bent.